The present invention relates to a uniform speed joint and an axial piston pump using the joint and, more particularly, to a uniform speed joint suitable for connecting a driving member and a driven member at highly precise uniform speed and an axial piston pump using the joint.
Universal joints in each of which a driving member and a driven member are connected through drive pins, the ends of which are fixed to the driving member and the other ends of the drive pins are slidably inserted in spherical bearings the circumference of which are engaged with the driven member, have been described in JP A 63-308220 or, JP B 4-72072, for instance.
Further, describes an improved arrangement in which drive pins are slidably inserted in a driving member, spherical head portions each are made in one piece with the drive pins, and a universal joint is constructed by engaging them with a driven member.
The known universal joint is constructed so that a difference in the pitch circle of drive pins changing position according to their change in inclination angle between the driving member and the driven member is compensated. However, since the driving member and driven member are connected by a pair of the drive pins, speed change takes place twice per one revolution. Therefore, the speed becomes nearly uniform, but it has deficiency that the rotation can not be transmitted at precisely uniform speed. Accordingly, problems such as mechanical vibrations or rotation noises are not solved.
In the known universal joint, since the bending stress necessary to transmit rotation is applied to the drive pins, slide resistance is large and, in particular, becomes a rotation load at high speed rotation whereby uniform rotation is not achieved. Therefore, in this case, also, even if rotation becomes uniform, problems such as mechanical vibrations and rotation noises are not solved.